Interferometry using undulator sources

Journal Article · Sun Sep 01 04:00:00 EDT 1996 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.1147396· OSTI ID:389543

Beguiristain, R; Goldberg, K A; Tejnil, E; Bokor, J; Medecki, H; Attwood, D T; Jackson, K ^[1]

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1. Center for X-ray Optics, Lawrence Berkeley Laboratory, 1 Cyclotron Rd., MS 2-400, Berkeley, CA 94720 (United States)

Optical systems for extreme ultraviolet (EUV) lithography need to use optical components with subnanometer surface figure error tolerances to achieve diffraction-limited performance [M.D. Himel, in {ital Soft} {ital X}-{ital Ray} {ital Projection} {ital Lithography}, A.M. Hawryluk and R.H. Stulen, eds. (OSA, Washington, D.C., 1993), {bold 18}, 1089, and D. Attwood {ital et} {ital al}., Appl. Opt. {bold 32}, 7022 (1993)]. Also, multilayer-coated optics require at-wavelength wavefront measurement to characterize phase effects that cannot be measured by conventional optical interferometry. Furthermore, EUV optical systems will additionally require final testing and alignment at the operational wavelength for adjustment and reduction of the cumulative optical surface errors. Therefore, at-wavelength interferometric measurement of EUV optics will be the necessary metrology tool for the successful development of optics for EUV lithography. An EUV point diffraction interferometer (PDI) has been developed at the Center for X-Ray Optics (CXRO) and has been already in operation for a year [K. Goldberg {ital et} {ital al}., in {ital Extreme} {ital Ultra} {ital Lithography}, D.T. Attwood and F. Zernike, eds. (OSA, Washington, D.C., 1994), K. Goldberg {ital et} {ital al}., Proc. SPIE {bold 2437}, to be published, and K. Goldberg {ital et} {ital al}., J. Vac. Sci. Technol. B {bold 13}, 2923 (1995)] using an undulator radiation source and coherent optics beamline at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. An overview of the PDI interferometer and some EUV wavefront measurements obtained with this instrument will be presented. In addition, future developments planned for EUV interferometry at CXRO towards the measurement of actual EUV lithography optics will be shown. {copyright} {ital 1996 American Institute of Physics.}

• OSTI ID: 389543
• Report Number(s): CONF-9510119--
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 9 Vol. 67; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
ADVANCED LIGHT SOURCE
ALIGNMENT
EXTREME ULTRAVIOLET RADIATION
INTERFEROMETRY
OPTICAL SYSTEMS
SOFT X RADIATION
USES
X-RAY EQUIPMENT